1. Field of the Invention
This invention relates to a sealing element for use with components of buildings, such as wall and floor elements, doors or the like, comprising an at least partly enclosed carrier strip consisting of a material which is self-foamable under the action of heat, e.g., a sodium silicate material.
2. Description of the Prior Art
A sealing element of this kind for use with doors has been disclosed in Austrian Patent Specification No. 353,460. That known sealing element comprises a substantially channel-shaped sheet metal bar, which contains a layer that is adapted to foam under the action of heat. A special design of the sheet metal bar with flanges at its legs has been proposed in order to facilitate the expansion of the bar in case of a fire. A sealing rubber element for contacting the door leaf is provided in addition to said fire barrier seal.
The use of a special sheet metal bar is expensive and its installation is complicated. Problems arise also owing to the expansion of the bar, as is apparent from Austrian Patent Specification No. 353,460. If a sheet metal is selected which is too strong, the bar may not be able to expand. Bars made of thinner sheet metal may easily be bent or may protrude in the course of time so that the function of the door will be adversely affected.
In connection with doors, particularly with fire barrier doors, it is known to provide sealing elements comprising a profiled plastic bar, which has a sealing base portion adapted to be inserted into a groove of the door frame and a sealing lip for engaging the door leaf or the door stop. To install such known sealing elements, the base portion is inserted into a groove of the door frame and in most cases extends around the entire door frame. In such a case the sealing lip effects a seal between the door frame and the marginal portion of the forward or rear side of the door leaf. In door frames made of wood, the base portion of the sealing element extends in a relatively narrow groove that has been milled into the door frame. in door frames made of steel the groove is formed in the profiled sheet metal bar of the frame and is usually wider than in door frames of wood and often flares toward the bottom of the groove.
Such sealing elements may be used also with fire barrier doors but this will involve certain disadvantages. In the first place the plastics usually employed for such sealing elements assume the plastically deformable semisolid consistency at elevated temperature so that their sealing action will be adversely affected. In a second place a gap is left between the door frame and the edges of the door leaf and flue gases and flames may pass through that gap. Such gap cannot be avoided, particularly with door leaves having no rabbet. The gap is the result of inevitable tolerances and is required to facilitate the opening and closing of the door.
Other doors are known, which are effectively sealed and do not define open gaps. But said known doors are highly expensive because they require door frames having intricate profiled shapes and also require a plurality of sealing elements.